Prague - Slovakia was set to ratify the European Union's reform treaty Thursday as an opposition party agreed to vote in its favour alongside the leftist government of Prime Minister Robert Fico.

The Party of Hungarian Coalition agreed to support the treaty during a vote scheduled for 5 pm (1500 GMT) Thursday.

"This is a one-time decision. It pertains only to the Lisbon Treaty. It pertains to preserving Slovakia's reputation," party leader Pal Csaky told a news conference televised by the TA3 news channel.

The Slovak Hungarian lawmakers thus broke ranks with the rest of the parliamentary right-wing opposition that has been blocking the ratification in order to push premier Fico into altering a controversial press law.

Publishers and human rights group see the law as a threat to the freedom of the press because it introduces expansive rights to reply to published articles.

The boycott however failed as government lawmakers passed the bill Wednesday without dropping all the contentious provisions.

"We just don't have arguments as to how the situation would have changed in May, June or September," Csaky said.

He said that the minority party plans to introduce law's amendment and analyze whether to have the bill reviewed by the Constitutional Court.

Slovak media speculated, citing unspecified parliamentary sources, that the party swapped Lisbon Treaty support for government assurances that a draft education law, set to go before parliament in May, would not introduce unwelcome changes for the Hungarian community.

"There are no deals," Csaky insisted.

An estimated 500,000 Hungarians live in the central European country of 5 million.

Slovakia was set to become the ninth EU member to ratify the Lisbon Treaty which had been painstakingly negotiated to overhaul institutions in the enlarged 27-member bloc.

Provided ratification by all members before the year-end, the reforms stemming from the treaty are likely to be introduced during 2009. Ireland is the only country to hold a referendum.